Sedimentary Systems And Favorable Sandstone Bodies Distribution Of The Second Member Of Funing Formation And The First Member Of Dainan Formation In Jinhu Sag

Based on previous research,supplement to new well bore,seismic,and analysis data,the sedimentary microfacies types,facies distribution and evolution characteristics of the second member of Funing formation?E₁f₂?and the first member of Dainan formation?E₂d₁?in Jinhu sag were analyzed,which made sub-member or sand body as a unit;through fine sand body analysis,the sand body distribution characteristics was confirmed,and the geological model of sand body development was established,who pointed out for finding and predicting favorable sand bodies.The research shows,E₁f₂ developed delta facies and lake facies,it was the evolution process of the positive cycle,with the continuous expansion of the lake basin,the deepening of the water body and the continuous shrinking of the depositional system,which was a typical water-type delta deposit.The sand body type is the subaqueous branch channel sand body of the delta front edge subfacies and beach bar sand body of Shallow lake subfacies,with the characters of thin layer,great number and longitudinal multiple sand bodies,which form the geological model with extensive distribution and frequent changes in the plane.The slope to deep depression of Sanhe sub-sag has the tectonic setting,which can form the local enrichment of the sand body,and it is also a favorable area of sandstone development.According to the analysis of detrital component,the composition and distribution of heavy minerals,variation trend of sandstone percent content,the two main source system of E₂d₁ member in the Jinhu sag was redefined,the supply of source system is abundant.In the fault depression pattern of"South fault north onlap",the continental clastic deposition such as delta,fan delta,underwater fan and sublacustrine fan,are formed,with the character of filling overburden deposition.The factors such as paleogenomorphology,fault slope,material source and hydrodynamic have important control effect on the distribution of sand body,it is clear that the delta front underwater distributary channel sand body,the gravity flow sand body in Sanhe sub-sag and underwater distributary channel of the delta front edge in the Longgang sub-sag have the potential to form subtle traps,which is more favorable.